So my engine rebuild is almost done, and everything looks good. There were a some very surprising things once the engine was opened up.

First thing was that the engine was already ported (which was going to have a medium street port done) it turned out that the port that was done was actually a large port so I lucked out there.

The next thing was that the rotors were scalloped, which I had never heard of till now. Chris (I don't remember his forum name) said it was a good thing. I was wondering if someone could elaborate on this for me and help me understand what kind of benefit I get from these?

 

1. opens the port earlier
2. less weight

 

So does it give any extra power? Better low end? Better top end? Can you elaborate more on the ports opening earlier and why it is beneficial?

 

better top end, like having a larger port

 

So no actual hp gains from this them?

 

They increase flow like larger ports so yes you should have more power. But like everything, ive never seen before after dynos

 

And unfortunately since my engine apparently had them you wont be seeing a before dyno here either, but you will see an after.

Another question how should they act in conjunction with a larger port, since I apparently have a larger port already done and the rotors were scalloped already. The only issue we found was that the exhaust pets were left stock after the large port was done and we didn't know why it was like that

 

Lost of low end torque with the scallops but it will make up for it on the top end.
Sounds like a bridgeport and behave like a bridgeport 2.

 

Yeah it always sounded extremely loud especially with my 3 inch exhaust, now how loud will it be since now the exhaust port will match the intake ports as a large port? Lol

 

in a bubble ... typically, earlier opening can show improvement in torque to a point. if you think of the Renesis (street oriented) and a bridgeport (race oriented), then that a generalized illustration of my point. the Renesis is basically a streetport from the factory and it also incorporates bevels/scallops - though they are nowhere near as extreme as yours.

however, you already mentioned that your engine has big streetports and i will assume that that probably included much later closing. so you've probably already gone into low velocity at low RPM terriotory where there may be a lope in the idle. only you can speak on that at this point.

is your car turbocharged?

 

Turbo 2 model with a t3/4 hybrid turbo 50 trim, no loping idle. At least there wasn't before the rebuild, I don't know after.also you mentioned that the bevel is extensive, what do you mean by that?

 

i was just saying that compared to some, yours have a lot of material taken out of them. they're not the MOST extreme i've seen though. if memory serves i think i saw a CLR set (or maybe it was Defined) that basically left only the recesses on the rotor face.

see if you can find a photo of a clean Renesis rotor and carefully look at that compared to yours, you'll see what i mean.

 

Okay I will check it out, so the renesis engine has cut rotors? I didn't know that

 

It should be brap with the scallops.............................

Well maybe not.The cuts are tiny compared 2 others than i seen.

 

Doesn't 'brap' or an idle 'lope' partly come from early opened intake/late closed exhaust also known as port overlap? Maybe the reason it didn't brap is because the exhaust ports were left stock, or not closing late enough to induce a rough idle. Furthermore, I thought the rotor scallops helped close the intake side ports later, not open them earlier. I guess if the scallops were severe enough they would do both.

 

yes. the loping (the BRAP) comes from increased overlap. the stock exhaust ports would be my guess, but other factors could be at play as well.

as for the opening-closing question with the bevels. remember that there is a lead side and trail side to the rotor, so the same bevel that opens the port has nothing to do with closing it.

 

I wish there was more information on the beveled rotors because I see different styles (or cuts) that people do so I would like to know if there are benefits on cutting them a certain way

 

probably just comes down to application.

i see you're in Miami. you should try to find Carlos Lopez. a few minutes of conversation with him would be worth your time.

i just thought about this and it's not entirely true.

 

You might get a lot of results for that name down there if you don't know where your looking

 

It is an extremely good thing. Consider yourself very lucky. Beveling or scalloping rotors is nothing new. It has only come into the lime light in the last few years. Before that it was mainly kept hush hush in the drag racing and road racing scene.

It's usually around a $300+ job with mandatory balancing. Another $300. You have a sweet rotating assembly sitting there and you didn't even have to send out and pay for the work...

Lucky you.

If you do not want to keep them, PM me. I would be interested in them for sure...

 

well, i kinda assumed he'd have searched the name here before he went looking. i've spoken to him (but this was maybe 7 years ago) so i know his contact information is on here somewhere. you could also google "Carlos Lopez Racing" or "CLR rotary".

 

Oh I know I'm lucky, you have no idea how lucky, lol. The previous owner didn't know it had cut rotors or that it was even ported. I bought the car in running conditions year ago for 3500 it came with all the mods and everything:

770 primaries
1600 secondaries
Lt8 microtec
T3/4 50 trim
Front mount intercooler
3mm superseals
255 walbro fuel pump
3 inch turbo back exhaust
Turbo xsManual boost controller
Hks ssq blowoff valve
Adjustable fpr
Large port on the intake
And of course the beveled rotors
There is probably more I'm forgetting but you get the idea.

When I got it out needed a tune and to turn up the boost cause it was only boosting 4 pounds due to a 4 pound spring in the wastegate

 

awesome! thanks for sharing the pics, ive seen lightened rotors but not cut ones before.

 

Defined's bevels are done by CLR, and yes they are more extreme.

 

I may be able to dig up a pre vs post scallop but there were other changes that would make it a bit more subjective. I know I had a big power increase and I think a small torque increase everywhere. But I also had better seals and stronger compression.

4 port NA.